A detailed interpretation of exciton lines caused by the presence of a lithium impurity in ZnO crystals (T = 4.2 K) was carried out. The 368.5-nm line is caused by radiative recombination of excitons bound on neutral donor states LiixThe 371.2-nm line is caused by the same process but occurring simultaneously with the transition of the donor to the excited state. The 368.2-nm line occurs when excitons bound on ionized Lii+states emit. The 369.7-nm line is the emission of excitons bound on acceptor complexes of the form (Zni+LiZn divide (Lii+LiZn divide etc. The measurements also made it possible to calculate the ionization energy of shallow donors Liix as E-d = 0.033 eV. Thus, a method for exciton spectroscopy of lithium states affecting the optical and electrophysical characteristics of zinc oxide has been developed.

Exciton luminescence spectra of ZnO crystals at 10–300 K were studied. Anomalous temperature dependences characteristic of exciton–phonon luminescence (EPL) of free excitons was observed in several ZnO samples at >150 K and could be interpreted as the manifestation of exciton–electron coupling. Temperature dependences of EPL of free excitons were closely related to defects and general destruction of the crystal translational symmetry so that a nondestructive quality-control method was needed. The conditions for recording unusual ZnO luminescence spectra associated with inelastic scattering of free excitons accompanied by emission of excited excitons and exciton–phonon complexes were described.

The sputtering of hot metal targets is a rapidly developing field in the technology of magnetron sputtering systems, aimed at solving certain challenges inherent in advancing the potential of magnetron sputtering: how to increase growth rate, the solution of a number of specific problems of reactive sputtering, and the sputtering of magnetic targets. Here the results of the sputtering of hot ZnO ceramic targets are reported for the first time. It was established that during hot sputtering the morphology of the erosion zone of a ZnO target when insulated from the thermal activity of a magnetron undergoes substantial modification at power density of P > 25 W/cm(2). The hot ZnO target emits microparticles that play a major role in the process of film formation on the substrate. It was shown that the crystallization of ZnO involving microparticles in the process of magnetron sputtering of a hot target occurs through the liquid crystal mechanism. A maximum growth rate (15 nm/s) of (0001) ZnO/(0001) Al2O3 epitaxial films with high structural perfection and intense luminescence in the violet region of the spectrum was achieved (currently a record rate).

Magnetic anisotropy values are obtained for [(Co 41 Fe 39 B 20 ) x (SiO 2 ) 100 – x /Bi 2 Te 3 ] 47 heterostructures consisting of SiO 2 alternating layers, CoFeB nanoparticles distributed in them, and Bi 2 Te 3 layers with ferromagnetic resonance and magnetometry. The heterostructures have anisotropy of ~10 6 erg/cm 3 , which orients the magnetic moment in films plane. The films are not solid, but they disintegrate into CoFeB nanoparticles with an average diameter of 5 nm during deposition, which corresponds to the blocking magnetization temperature of ~30 K during their saturation magnetization of M S = 720 emu/cm 3 . The relationship between anisotropy constant and thickness of the layers of the heterostructures is nonmonotonic due to competition between surface and bulk anisotropies of the ferromagnetic granules, which the films are made of.

Orange and red photoluminescence spectra of copper iodide were studied and divided into four components with λ max ≈ 625–635 (O 1 ), 635–655 (O 2 ), 725–735 (R 1 ), and 735–755 nm (R 2 ) that were explained by possible association of the corresponding glow centers (GCs) with donor–acceptor pairs (DAPs) responsible for CuI edge luminescence. A generation-recombination scheme for red–orange luminescence was developed based on Auger interaction of GCs and DAPs. Intrinsic interstitial Cu defects acted as GCs for red CuI luminescence. Methods for controlling CuI luminescence characteristics by annealing crystals (in I 2 vapor, in vacuo), doping with Li, or saturation of samples with electrodiffused Cu were demonstrated.

The article reviews researches, conducted by the department of physics of Moscow State University of Railway Engineering (MIIT), the results of which can be used or are being used in the transport sector, namely with regard to: 1) development of optimization models regarding types of trucks; 2) improving design and creation of new types of electroluminescent indicators; 3) refinement of wheel-rail contact theory. General conclusion proposed by the authors and concerning practices of rail related studies is that physics plays one of the most important roles in teaching and learning processes, as well as in conducting a wide range of researches in a transport university.

The review of the spectrometer researches conducted in Scientifical educational center of photonics, tool informational and analytical technologies (SEC PIAT) at department of physics of MGUPS (MIIT) is given. Application possibilities of the modern spectrometer equipment in educational process and familiarizing practice students, graduated students and teachers with the hi-tech equipment are discussed.

Ways of enhancing the free exciton UV radiation intensity of zinc oxide single crystals by means of thermal treatment in controlled environments, and by adjusting their stoichiometric composition during growth, are considered. It is shown that the intensity of exciton-phonon luminescence can be increased and the composition of radiation spectra can be varied through the high-temperature annealing of samples. The ways of achieving this depend on the technique used for crystal growth.

High quality ZnO single-crystal films were doped with copper by thermal diffusion, and their luminescent properties were studied by cathodoluminescence spectroscopy. Doping with copper increases the intensity of the green-emission band of the cathodoluminescence spectrum, whose peak, width, and shape at 78 and 300 K remain unchanged. At 4.2 K, a pronounced phonon structure with a phonon energy of 72 meV is detected in the cathodoluminescence green-emission band of the doped samples. In this case, the phonon peaks feature a triplet fine structure instead of the doublet one generally observed. This feature is attributed to radiative recombination of acceptor excitons that are localized at copper atoms and interact with each one of the subbands of the ZnO valence band. An analysis of the experimental data on the film cathodoluminescence and comparative studies of luminescence and electron spin resonance in single crystals allow one to conclude that the uncontrollable copper impurity typically existing in ZnO is responsible for green-emission luminescence in this material.

It is reported on the fabrication and characterization of light emitting n-ZnO/p-GaN heterojunction. Firstly, a Mg-doped p-GaN layer was grown on (0001) sapphire substrate by the molecular-beam epitaxy technique, then thin Ga-doped n-ZnO film was deposited by the chemical vapor deposition in the low-pressure system. Diode-like rectifying behavior of this heterojunction and room temperature electroluminescence in the blue-violet region with peak wavelength 430 nm under forward bias were observed. Light-current characteristics of this structure feature a superlinear behavior in the low current range with a slope 1.9 and a sublinear behavior with a slope 0.85 in the high current range.

The radiation defects created in hydrothermal ZnO–Li single crystals by irradiating them with electrons, protons, and high‐energy ions have been investigated. The anionic vacancies (F‐centers) in ZnO are established to be the centers of radiationless recombination of the charge carriers with a photoionization energy of 2.3 eV (a signal of the photo‐EPR with the g ‐factor for the F + ‐center: g ∥ = 1.9948 and g ⊥ = 1.9963). The anionic vacancies in the form of the F and F + states are a good reference of the electron and hole processes. The [F Li ] × ‐centers that correspond to the oxygen vacancies localized near the point defects Li Zn are detected. In the temperature range 530–660 K, ZnO crystals display thermally stimulated processes such as the healing of anionic vacancies (530–630 K) and the disappearance of the [F Li ] × ‐centers (610–660 K).

The principal results of the investigation of thermally stimulated electron–hole and ionic processes in hydrothermal and gas-phase ZnO single crystals preexcited at low temperatures, based on simultaneous study of photo-EPR and thermoluminescence (TL), are presented. The nature of the traps determining the TL peaks at 17, 24, 40, 53, 90–110, 140–150, and 160–200 K is discussed. In particular, it has been established that the lithium paramagnetic centers (Li Zn + –O I ) play the role of hole traps in ZnO giving green and red TL in the temperature range 160–200 K and, in the case of association with small-sized donors, also TL in the temperature range 90–110 K. The other traps are electronic in character, and in the presence of acceptor lithium in the crystals, they form yellow-orange TL. Optical quenching of TL has been evaluated, and it has been found that there is a difference Δ E ≈ 0.75 eV between the thermal and optical energies of ionization of lithium acceptors. Irreversible ionic processes associated with the “healing” of cationic vacancies at T ≈ 360–420 K have been revealed.

It is shown that changes in luminescence characteristics of zinc sulfide and oxide in the presence of external effects that alter the surface charge are associated with a change in the parameters of surface barriers and can be explained within the framework of a model that takes into account separation of recombining partners in the Schottky barriers. We suggest a barrier mechanism for the effect of the surface region of a crystal on experimentally measured luminescence parameters and show that errors occuring in the measurement of these parameters can reach 10% and greater, depending on the depth of penetration of light.

Cerium- and terbium-doped yttrium oxosilicate single crystals suitable for applications as scintillators and in radiochromatography are grown. The crystals are competitive with the commonly used powder scintillators sensitive so beta-radiation, as they have comparable luminescent properties and can be prepared with controlled dimensions.

Lithium paramagnetic centers (Li-Zn(+)-O') in ZnO act as hole traps responsible for green and red thermoluminescence in the temperature range 160-200 K. The difference between the thermal and optical ionization energies of lithium accepters is Delta E approximate to 0.75 eV. Single-crystal ZnO(Li) is shown to be a candidate material for optical memory elements.

The distribution of the lengths of the tracks, created by 90 Mev Carbon ions in Zno crystal consists of three groups with an average value about 52, 67 and 102 micrometers. The first group of the tracks may be treated as unchannelling particles. The second group corresponds to channeling particles and the third one represents superchannelling particles.